Tricyclobutabenzene

Tricyclobutabenzene
Names
	Preferred IUPAC name Tetracyclo[8.2.0.02,5.06,9]dodeca-1,5,9-triene
Identifiers
CAS Number	60323-52-6 [pubchem];
3D model (JSmol)	Interactive image;
ChemSpider	126777 ;
PubChem CID	143698;
CompTox Dashboard (EPA)	DTXSID70209083 ;
	InChI InChI=1S/C12H12/c1-2-8-7(1)9-3-4-11(9)12-6-5-10(8)12/h1-6H2 Key: MTPUNWSZJLTTLU-UHFFFAOYSA-N ; InChI=1/C12H12/c1-2-8-7(1)9-3-4-11(9)12-6-5-10(8)12/h1-6H2 Key: MTPUNWSZJLTTLU-UHFFFAOYAI;
	SMILES c12c4c(c3c(c1CC2)CC3)CC4;
Properties
Chemical formula	C12H12
Molar mass	156.228 g·mol−1
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). verify (what is ?) Infobox references

Tricyclobutabenzene is an aromatic hydrocarbon consisting of a benzene core with three cyclobutane rings fused onto it. This compound and related compounds are studied in the laboratory because they are often displaying unusual conformations and because of their unusual reactivity. Tricyclobutabenzenes are isomers of radialenes and form an equilibrium with them.

The parent tricyclobutabenzene (C₁₂H₁₂) was first synthesised in 1979^[1] by the following sequence:^[2]^[3] This compound is stable up to 250 °C (482 °F).

A polyoxygenated tricyclobutabenzene with an extraordinary bond length of 160 pm for the bond connecting two carbonyl groups^[1] by the following sequence:^[4]

An ordinary bond of this type is only 148 pm and for comparison the C-C bond in isatin is 154 pm long. On the other hand, no change is recorded in the aromatic bond length alternation.

Similar chemistry yielded the six-fold ketone hexaoxotricyclobutabenzene C₁₂O₆, which happens to be a novel oxide of carbon.^[5] A key starting material is the iodo triflate depicted below which is a benzotriyne synthon.

References

^ Tricyclobutabenzene Wutichai Nutakul, Randolph P. Thummel, Austin D. Taggart J. Am. Chem. Soc.; 1979; 101(3); 770-771. doi:10.1021/ja00497a064
^ Reaction sequence: coupling reaction of cyclobutene Grignard reagents followed by Diels–Alder reaction with dimethylcyclobutene-1,2-dicarboxylate, followed by ester hydrolysis to dicarboxylic acid with potassium hydroxide in methanol followed by decarboxylation and aromatization with lead tetraacetate
^ Poly-Oxygenated Tricyclobutabenzenes via Repeated [2 + 2] Cycloaddition of Benzyne and Ketene Silyl Acetal Toshiyuki Hamura, Yousuke Ibusuki, Hidehiro Uekusa, Takashi Matsumoto, and Keisuke SuzukiJ. Am. Chem. Soc.; 2006; 128(11) pp 3534 - 3535; doi:10.1021/ja0602647
^ Reaction sequence: the key step is a [2+2] cycloaddition between an aryne formed from the iodotriflate by action of n-butyllithium and a ketene silyl acetal. The silyl acetal is then converted to a ketone group by hydrofluoric acid and the remaining acetal groups by reaction with boron trifluoride
^ Dodecamethoxy- and Hexaoxotricyclobutabenzene: Synthesis and Characterization Toshiyuki Hamura, Yousuke Ibusuki, Hidehiro Uekusa, Takashi Matsumoto, Jay S. Siegel, Kim K. Baldridge, and Keisuke Suzuki J. Am. Chem. Soc.; 2006; 128(31) pp 10032 - 10033; doi:10.1021/ja064063e

[1] Tricyclobutabenzene Wutichai Nutakul, Randolph P. Thummel, Austin D. Taggart J. Am. Chem. Soc.; 1979; 101(3); 770-771. doi:10.1021/ja00497a064

[2] Reaction sequence: coupling reaction of cyclobutene Grignard reagents followed by Diels–Alder reaction with dimethylcyclobutene-1,2-dicarboxylate, followed by ester hydrolysis to dicarboxylic acid with potassium hydroxide in methanol followed by decarboxylation and aromatization with lead tetraacetate

[3] Poly-Oxygenated Tricyclobutabenzenes via Repeated [2 + 2] Cycloaddition of Benzyne and Ketene Silyl Acetal Toshiyuki Hamura, Yousuke Ibusuki, Hidehiro Uekusa, Takashi Matsumoto, and Keisuke SuzukiJ. Am. Chem. Soc.; 2006; 128(11) pp 3534 - 3535; doi:10.1021/ja0602647

[4] Reaction sequence: the key step is a [2+2] cycloaddition between an aryne formed from the iodotriflate by action of n-butyllithium and a ketene silyl acetal. The silyl acetal is then converted to a ketone group by hydrofluoric acid and the remaining acetal groups by reaction with boron trifluoride

[5] Dodecamethoxy- and Hexaoxotricyclobutabenzene: Synthesis and Characterization Toshiyuki Hamura, Yousuke Ibusuki, Hidehiro Uekusa, Takashi Matsumoto, Jay S. Siegel, Kim K. Baldridge, and Keisuke Suzuki J. Am. Chem. Soc.; 2006; 128(31) pp 10032 - 10033; doi:10.1021/ja064063e

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Tricyclobutabenzene

See also

References

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